Treatment of hydrocarbon oils



Patented June 6, 1933 STATES PATENT OFFICE MAYFIELID C, SUMPTERp-OF CHICAGO, ILLINOIS, ASSIGNOR .TO UNIVERSAL OIL PROD- UGTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA TREATMENT OF HYDROCARBON OILS No Drawing.

This invention relates to the treatment of hydrocarbon oils, and refers more particularly to the treatment of the lighter distillates produced from the primary or straight distillation of crude petroleum or other similar hydrocarbons, or from the cracking of heavy hydrocarbon mixtures.

More specifically, the invention contemplates the provision of a process adapted to selectively remove gum and color-forming constituents and sulfurfrom relatively low boiling hydrocarbon mixtures, such as are encountered, for example, in the cracked products of heavy oils.

. Extensive researches have been conducted with the object of devising treating methods capable of efficiently and selectively removing such unsaturated compounds as diand triolefins from cracked distillates because of theirobjectionable gum and .coloi forming properties, while leaving unaffected the less highly unsaturated groups, such as the mono olefins, which have the characteristic of adding to the anti-knock value of the distillate, while adding only slightly, if at all, to its gum or color-forming tendencies.

Another series of treating researches has been concerned with the removal of sulfur compounds, such as mercaptans, sulfides, thiophenes and the like, efforts being directed to the removal ofthese compounds as such, or their decomposition into easily removable sulfur and new hydrocarbon radicals.

In a majority of cases, it has been found that the reagents capable of reacting with the highly unsaturated hydrocarbons, react concurrently with the more easily reactive sulfur compounds, particularly in view of the fact that double linkages and sulfur are sometimes present in the same molecule.

The process of the present invention is concerned with the use of a specific classofchemical reagents capable of effecting the two main results desired in treating cracked distillates, to-wit: The controllable reduction of unsaturation by removal of diand tri-olefins, and the reduction of sulfur content to a point consistent with the economies involved.

In one specific embodiment of the invention cracked distillates, either in liquid orvapor- Application filed May. 11,

phase, are subjected to treatment with an oxychloride, or with a mixed-base oxychloride, the degree of treatment being controlled by the decomposition of the reagent and the conditions under which it may be applied;

It has been knownfor a considerable length of time that oxychlorides of the heavy metals could be prepared from concentrated aqueous solutions by various methods. In one method, the double compound may be precipitated by the addition of an oxide of the metal to the concentrated chloride solution. In other cases, an oxychloride may precipitate upon a concentration of the solution toa certain point by evaporation of the solvent, a corresponding amount of hydrochloric acid being evolved. Another method consists in forming a paste with the oxide and adding the paste to a hot solution of the chloride. This latter method has been employed in making several of the oxychlorides of zinc, a great many of which have been described in the literature. As examples of some zinc oxychlorides which have been isolated as chemical individuals, the folowing are representative:

ZnCl -ZnO'QH O ZnOI 'ZnO-H O ZnCl 5Zn0- 81-1 0 ZnCl -9ZnO-3H O Similarly, a large number of mixed-base oxychlorides may be prepared and utilized in the process of my invention. For example, a zinc-lead oxychloride can be prepared by treating a concentrated solution of zinc chloride with lead oxide (PbO) (litharge). This oxychloride may be found to have the formula 3(Z11O12-3Z11O) 2(PbG1 -PbO) 1411 0 A zinc-copper oxychloride can be formed by addingcupric oxide (CuO) to a concentrated zinc chloride solution. This results in the formation of the following compound (Z nCl ZnO- CuO) (ZnCl 30110) 611 0 By similar methods, an extensive series of mixed-base oxychlorides may be formed. For example, I have formed oxychloride mixtures of zinc and tin, of zinc and cadmium, and others.

In the practice of the process of my invention, wherein amixed base oxychloride is employed, the mixed character of the oxychloride compound affords advantageous means for accurately controlling the nature of the treatment of a cracked distillate, it being possible to so proportion the base elements that either removal. of highly unsatu- 'ated compounos can be effected independent of sulfur reduction, or sulfur reduction can be effected without undue loss of olefinic constituents in the distillate under treatment. By a suitable and proper choice of reagent, the action upon sulfur compounds may be limited, for example, to a sweetening-action, comparable to that produced by the so-called doctor solutions, which are solutions of litharge in caustic soda of varying strength.

In carrying out my process, the hydrocarbons may be subjected to treatment thereunder in either the liquid or vapor phase. In the liquid-phase treatment of cracked distillates, temperatures are preferably utilized which will maintain the oxychloride salts in a substantially liquid state, such temperatures being of the order of about 200 F. to about 350 F. The vapor-phase treatment of the hydrocarbons is preferably carried out by impregnating porous filler bodies with fused zinc oxychlorides, or the double metallic oxychlorides, after which the filler body may be disposed within a suitable treating tower through which the hydrocarbon vapors may pass.

It is to be understood, of course, that any desired apparatus may be employed in carrying out the process of my invention, and during the course of treatment, advantage may be taken of the variable physical as well as chemical properties of the mixed-base oxychlorides. For example, a cracked distillate containing a finely divided reagent in suspension may be distilled under suitable pressure to permit proper treatment of the lower boiling fractions prior to their evolution as vapor; or in other instances the cracked distillate may be distilled with steam at relatively low temperatures in the presence of molten or fused reagents or concentrated solutions, contact being effected by the stirring action of the steam and the ebullition of the liquid. In other instances wherein a filler body is utilized, such body may comprise a relatively inert supporting or spacing material, such as pumice, fullers earth, porous porcelain or the like, coated or impregnated with the reagent and placed in'a composite contact mass in superimposed layers throughout a treating tower or towers utilized for the fractionation of vapors. In the practice of this method, it may at times be advantageous to add solutions or suspensions of the treating reagent at the top of the tower and allow concurrent action, thus causing the original reactive agent in the tower to be continuously replenished. In a further embodiment, the fused reagent may be caused to pass countercurrent to the vapors being treated in a. tower.

As an example of the results obtainable by a treatment embraced within the scope of the invention, the following is illustrative A California cracked distillate may be distilled in the presence of about 1% by weight of zinc-tin oxychloride under a pressure of about 50 to 100 pounds per square inch in order to insure the attainment of temperatures necessary for reaction before the lighter ends are distilled. The distillate, prior to treatment, may be of a dark, reddish brown color, with a gum content by the copper dish method of 600 1ngs., a sulfur content of 0.4%, and a final boiling point of approximately 500 F. It will be found that the first 80% distilled over will have a final boiling point of about 410 F., a color of plus 25 on the Sayboltscale, a gum content of approximately 50 mgs, and a sulfur content of about 0.2%. In addition, the color stability, as measured by the four-hour sun exposure test, may be represented by a loss of less than 2 points on the Saybolt scale, and the distilled gasoline will be found to react negatively with the plumbate solution used in the so-called doctor test.

While the foregoing example and description will serve to indicate some of the modes and methods of operation and the results obtainable by an adaptation of the process of my invention, it will be readily apparent that the invention is adaptable to a wide variety of uses, and that the foregoing is not to be taken as in anyWise a limitation upon the broad scope of my process.

I claim as my invention 1. A process for refining hydrocarbon oils, which comprises subjecting said oils to treatment in the presence of a mixed-base oxychloride.

2. A process for the treatment of hydrocarbon oils, comprising passing a distillate through a treating zone for reaction therein inrthe presence of a mixed-base oxychloride.

3. A process for the treatment of hydrocarbon oils, comprising passing hydrocarbon vapors through a treating zone for reaction therein in the presence of a mixed-base oxychloride.

In testimony whereof I aifix my signature.

MAYFIELD C. SUMPTER. 

